目的 了解海南省白纹伊蚊对常用杀虫剂抗性水平及其击倒抗性(knockdown resistance,kdr)和乙酰胆碱酯酶1(acetylcholnesterase number one,ace-1)基因的突变情况.方法 分别于2020年和2021年在海南省儋州、三亚、琼中、琼海、昌江和万宁采集白纹伊蚊幼虫,测定其对常用杀虫剂的抗药性,抽取抗性测定存活样品并对其kdr基因和ace-1基因的突变进行检测.结果 海南不同地区白纹伊蚊种群成蚊接触溴氰菊酯(0.03%)、氯菊酯(0.40%)、高效氯氰菊酯(0.40%)、高效氯氰菊酯(0.08%)和高效氯氟氰菊酯(0.07%)药膜 24h后的死亡率分别为 5.56%～83.33%、29.89%～92.22%、26.67%～97.78%、11.11%～88.89%和40.00%～83.33%;接触残杀威(0.05%)、噁虫威(0.20%)、马拉硫磷(0.50%)、杀螟硫磷(0.20%)、毒死蜱(2.00%)5种杀虫剂药膜24h后死亡率为94.89%～100.00%,其中昌江白纹伊蚊种群接触残杀威的死亡率为97.78%,三亚、万宁和琼海白纹伊蚊种群接触马拉硫磷的死亡率分别为94.89%、96.67%和96.67%,三亚和琼海白纹伊蚊种群接触杀螟硫磷的死亡率均为97.78%,其他种群死亡率均为100.00%.聚合酶链式反应产物测序结果显示kdr基因仅1534位点存在突变,共有4种等位基因,即野生型TTC/F和突变型TGT(TGC)/C、TCC/S、TTG/L,其突变频率分别为40.47%,22.25%、36.44%和0.85%,这些突变共组成7种类型,即野生型纯合子F/F,野生型/突变型杂合子F/C、F/S和F/L,突变型杂合子S/C,突变纯合子C/C和S/S,其突变频率依次为19.92%、6.78%、32.63%、1.69%、11.44%、13.14%和14.41%.在ace-1基因对应的119位点未检测到相关氨基酸突变.结论 海南省6个地区白纹伊蚊对拟除虫菊酯类的溴氰菊酯、氯菊酯、高效氯氰菊酯和高效氯氟氰菊酯均产生较高抗性,而对氨基甲酸酯类和有机磷类杀虫剂敏感或产生可能抗性;抗性基因突变主要以kdr基因1534位点为主,其突变频率可能是导致海南地区白纹伊蚊产生抗药性的重要原因.
Investigation on resistance and resistance-conferring mutations in kdr and ace-1 genes in Aedes albopictus in Hainan Province
Objective To explore the tolerance of Aedes albopictus to typical insecticides and mutations in its knockdown resistance(kdr)and acetylcholinesterase number one(ace-1)genes in Hainan Province.Methods Ae.albopictus larvae were collected from Danzhou,Sanya,Qiongzhong,Qionghai,Changjiang,and Wanning in Hainan Province in 2020 and 2021 to assess their resistance to 10 insecticides.Surviving samples from the resistance tests were examined for mutations in genes encoding acetylcholinesterase(AChE)and voltage-gated sodium channel(VGSC)using DNA Sanger sequencing.Results The 24-hour corrected mortality rates of adult Ae.albopictus in different areas of Hainan to deltamethrin(0.03%),permethrin(0.40%),Beta-cypermethrin(0.40%),Beta-cypermethrin(0.08%),and lambda-cyhalothrin(0.07%)ranged from 5.56%to 83.33%,29.89%to 92.22%,26.67%to 97.78%,11.11%to 88.89%,and 40.00%to 83.33%,respectively.The mortality rates after 24-hour exposure to propoxur(0.05%),bendiocarb(0.20%),malathion(0.50%),fenitrothion(0.20%),and chlorpyrifos(2.00%)ranged from 94.89%to 100.00%,among which the Ae.albopictus population from Changjiang showed a mortality rate of 97.78%to propoxur,and populations from Sanya,Wanning,and Qionghai showed mortality rates of 94.89%,96.67%,and 96.67%to malathion respectively.The mortality rate of Ae.albopictus populations in Sanya and Qionghai to fenitrothion was 97.78%,while in other populations,it was 100.00%.Sequencing results showed that the kdr gene exhibited a mutation solely at locus 1534,featuring four alleles:wild-type TTC/F and the mutant types TGT(TGC)/C,TCC/S,and TTG/L with the mutation frequencies of 40.47%,22.25%,36.44%,and 0.85%,respectively.There are seven types of these mutations:wild-type homozygotes F/F,wild-type/mutant heterozygotes F/C,F/S,and F/L,mutant heterozygotes S/C,and wild-type homozygotes C/C and S/S,with mutation frequencies of 19.92%,6.78%,32.63%,1.69%,11.44%,13.14%,and 14.41%,respectively.Notably,No related amino acid mutations were detected at position 119 of the ace-1 gene.Conclusions The Ae.albopictus populations in various areas of Hainan Province have developed a high resistance to pyrethroid insecticides such as deltamethrin,permethrin,beta-cypermethrin,and beta-cyfluthrin,but are sensitive or possibly resistant to carbamates and organophosphates insecticides.The resistance gene mutations mainly occur at position 1 534 of the kdr gene,suggesting that its mutation frequency could be a significant factor contributing to resistance in Ae.albopictus in Hainan.
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